errors_for
A polyfill ruby gem for the error_messages_for (http://apidock.com/rails/ActionView/Helpers/ActiveRecordHelper/error_messages_for) that was dropped in RoR 2.3.8.
Why it was removed: http://news.ycombinator.com/item?id=1263775
The gem can be used when migrating Rails project 2.x to 3+ as it will remove one less concern and issue to deal with.
Usage
gem "errors_for"License
errors_for is released under the MIT License.